Electronic stop control for motordriven switches having two-drive magnets



Oct. 12, 1954 H. PANZERBIETER ELECTRONIC STOP CONTROL FOR MOTOR-DRIVEN SWITCHES HAVING TWO-DRIVE MAGNETS Filed May 14, 1952 air Inventor? r f Patented Oct. 12, 1954 ELECTRONIC STOP CONTROL FOR MOTOR- DRIVEN SWITCHES HAVING TWO-DRIVE MAGNETS Hans Panzerbieter, Berlin-Siemensstadt, Germany, assignor to Siemens & Halske Aktien- Germany, a. corporation gesellschaft, Munich of Germany Application May 14, 1952, Serial No. 287,788

Claims priority, application Germany June19, 1951 This invention relates to switches used in signalling systems, e. g., automatic telephone systerns, and is particularly concerned with an electronic stop control for motor-driven switches having two drive magnets. The invention may be considered an improvement on the disclosure in copending application Ser. No. 281,626, filed April 10, 1952.

The two drive magnets of such a switch become alternately operative under the control of contacts governed mechanically by cams carried by the switch shaft so as to efiect the drive by the alternate actuation of the magnets. Control means are provided for stopping such a switch by simultaneously actuating the two drive mag- 2 Claims. (01. 17918) nets at' the instant when the switch wipers reach desired bank contacts. A switch of this type is disclosed in the German Patent No. 805,286, dated May 15, 1951, and motors of the type referred to are disclosed in copending application Ser. No. 259,076, filed November 30, 1951, now Patent No. 2,654,846 dated October 6, 1953 and also U. S. Patent No. 2,002,5e6.

One of the two drive magnets is, in a switch of this type, energized in a circuitincluding an associated closed control contact when its wipers reach engagement with desired bank contacts. The other drive magnet is at this instant inactive but must be energized, because stopping of the switch is eiiected by the simultaneous energizetion of both drive magnets. The energization of such other drive magnet is efiected by shunting its associated control contact to produce an energizing circuit path for the corresponding drive magnet. The shunting was, prior to the disclosure in copending application Ser. No. 281,626, accomplished by the contact springs of a test relay which energized at the instant when the wipers reached the desired bank contacts. The invention disclosed in this copending application proposes to effect the shunting of the mechanically governed control contact springs (of the drive magnet which happens to be deenergized when the switch should be stopped) over a discharge path in an electron discharge tube which becomes conductive responsive to a potential designating the stopping of the switch. The brake action can thus be initiated during the operation of the switch much faster than by the use of the electromagnetically operating test relay used in the past.

The present invention proposes to make the potential which designates the stopping of the switch, efiective on the grid of the discharge tube over a transformer. The use of the transformer makes it possible to retain the test and busy potentials usually employed in automatic telephone systems, as distinguished from the prior proposal which connects a stop potential directly to the tube, thereby requiring, in view of the necessary tube control, potentials which differ from the usual test and busy potentials.

Details of the invention will be brought out in the description of embodiments shown in the accompanying drawings, wherein Fig. 1 illustrates an embodiment in diagrammatic circuit representation; and

Fig. 2 shows a fraction of the circuit of Fig. 1, including a modified transformer.

Referring now to Fig. 1, there are two switches indicated by W1 and W2. These switches may be of the hunting type having test wipers 1001 and was which are advanced relative to bank contacts connected with conductors of the trunks or lines to hunt for an idle one of the trunks or lines. The conductors c1 and 02 are the test or private conductors of the corresponding trunks or lines. These conductors are in usual fashion multiplied so as to be accessible to a desired number of switches.

If it is now assumed that one of the switches, e. g., the switch W1, has found an idle line having the test conductor 01, there will result the following circuit: from negative battery v.) over resistor Wii, winding of relay C1, conductor 01, wiper wci standing on the bank contact 1, contact spring 2121, winding ll". of the relay P1 designated as P111, to ground. A busy potential of -5 volts is now connected over the multiple connected to the bank contacts I of all switches having access to the seized line 01, including the bank contact I of the switch We which is accessible to the wiper wee.

It may now be assumed that the switch W2 is seized. Such seizure causes actuation of the relay V2 in any desired manner known in the art. The operation of the switch W2 is under the con trol of two drive magnets diagrammatically indicated at M1 and M2. As has been mentioned befcre, the drive magnets are governed by contacts (m1 and me) which are mechanically controlled, e. g., by cam means, in such a manner that contact m1 connects the drive magnet M1 in an energizing circuit to cause rotation of an armature carried on the switch shaft until such a time when the switch shaft is angularly displaced toa point at which contact m2 is closed to energize the drive magnet M2, while the contact mrtis opened toi' disconnect magnet-M13; The rotation ofthe armature and=switch -shaftthen continues under the control of the magnet M2 until an angular switch shaft position is reached in which the contact ma is to disconnect magnet M2, while the c iitactameis cicseaato cause re-operation of magnet M1.

An idle line may be found, e. g, the line 02, extending from the banlflc'ontact Z WVhile the drive magnet M2 is operativei'over a circuitim cluding its closed associated'coiitrofcontacfmz. The switch must now be stopped by shuntin the open contact m1 so as to energizeitherinaignetf-Mi, since both magnets must be energizedrto effect the stop-ping.

The required shunting of the contact mi'is effected over the discharge path of theitub'e'Ri at the instant when the'lltube becomes conductive v,by connecting.-a -certain-potentialato its control grid. This-potential-is connectedat. the instant when the switch ,wipers reach bank contacts from which extend. the conductors of an idle line. The wiper wcs (the remaining wipers have been omitted to'avoid encumbering the-drawing-) first establishes-connection with the bank-vcontact l which carries a busypotential of 5 volts, 'as mentionedibeforef The transformer TrKFig. 1) having the :-primary winding pr connected with the wiper was; while its secondary :winding seis connected with'the dischargetube R1, does not-at thisminstant deliver an impulse for the grid of the tube Ri-which-is-sufficient to make the tube conductive. The-switch therefore continues- -to rotate. When the wiper wcareaches .the-ebankcontact" 2,- the line 02 emending therefronrbeing assumed to-be idle, A there will result a circuitfor theprimary winding of the transformer Tr from 60 v., resistor W52, relay 02, test conductor 02, wiper wca on bank contact 2, contact-1 pa primary winding prto -5 volts. The secondary windin Se now delivers an impulse to -the grid of the tube R1, making the tube cond-uctive toprovide acircuit path asa shunt for the contact inn-thus caiising the magnet M1 to operate and maintaining the operation ofvthe magnet Ma. The switch-stops with its Wipers in engagement with the seized line.

The winding I-of the relay P2, designated as P21, is energized in the tube circuitto operate its contact 3232, which shcrt-circuits the tube .while completing a l-iolding circuit for both drive magnets. The relay P2 also closes its contact 2m, to complete the busy circuit for the test conductor from ground over its winding II, which is designated as P2H. Accordingly, there is now a busy potential of volts on the test conductor 02. The closure of contactfipz of therelay P2 causes deenergization of-the relay V2 which was=energized before lat the time when theswitch was seized in known manner, which does not form part of the invention. Relay V2, upon-deenergizmg, opens its contact 5'02 to cause release of,the

magnets M1 and M2.

It will be appreciated that the use of the transformer permits production of a grid potential for makin .the --tube -l B1-.- conductive independent of the particular potential employed for testing and signalling =systems of the typediscussed.

The transformer Tn'shown in Fig. 1 may be replaced by an auto-transformer of the type shown in Fig. 2 at TTo. All other circuit elements remain as shown in Fig. 1. The operation of a circuit employing the auto-transformer TTo conforms to 5 that described with reference to Fig. 1.

I claim: 1: Err aigswitch for .useinasignalling system .of.the:class described having a plurality-of wipers and a drive motor for moving said wipers com- .10::-.prisin two drive magnetsand associated control contactsqfor causing said drive magnets to opereateiaiternately-gsoiasto advance said wipers with respect to-bank Xaontacts, one of said drive magnets and associated control contact being during the; actuation of said switch always operated while CF the 'iother drive magnet and associated control '"*-'cont'act"are"ineffective, and having stop control means including ajdischarge tube which becomes zoperativeighyea=-potential applied thereto at the instant when said switch wipers are in engagement' with desired bank contacts to energize the irifiective drive magnet so as to cause operation of such gdrive magnet while the other drive magnet is operated, to thereby effect stopping of said switch by the coactionbf the simultaneously operat'ed drive magnets; a device for controlling the operation oijsaid'discharge'tube, said device comprising a'-'transformer having a secondary Qwi'nding connected with electrodes of said discharge -tube, circuit means including the primary winding of saidtransformer and a switch wiper "for connectin a potential to said primary winding when said switch wiper engages a desired -,asso,ciated bank contact so as to cause current to flow" in said secondary winding which is adapt- 'ed to make saidcdischarge tube conductive, and control circuit means governed by said tube for energizing the ineffective drive magnet independent .of' the"control contact associated there- 40 with.

2;" In a switch' for use" in a signalling'system of the class described having a plurality of wipers and a drive motor for moving said'wipers. comprising two' drive magnets and associated control 'co'ntacts'for causingsaid drive magnets to operate alternatelyvso as to advance said wipers with respect to bank contactsjone of said'drive magnets and associated control contact being during the actuation of said switch always operated while the'other drive magnet and associated control oontact'are ineifective, and having stop control 'means'including a discharge tube which becomes operative by a potential applied thereto at the instant when'said switch wipers are in en- .gagementlwith bank contacts associated with 'conductorsiof a desired line to energize the ineffective drive-magnet so as to cause operation of suchdrivemagnetwhile the other drive magnet is operated, to-thereby effect stopping of said switch by the coaction of the'simultaneously operated'drive magnets; a device for controlling the operation'of said discharge tube; said device comprising a'transformer having a primary winding connected in circuit'with a-test wiper coacting- 5 with bank' contacts from which extend the'test conductors of lines accessible to said switch, circuit means extending from the secondary winding of said transformer-to electrodes of said discharge tube, theidle potential on a test conductor connected with a bank contact engaged by said test wiper causing said transformer to produce in its secondary winding an operating impulse for said discharge tube to make said tube conductive, control circuit: means governed. bysaid tube for energizing the inefiective drive magnet inde- 2,691,699 5 6 pendent of the control contact associated thereductor of the desired line engaged by said test with while the other drive magnet is energized wiper. so as to stop the switch with its wipers in engagement with bank contacts connected with the References Cited in the file of this patent conductors of a desired line, a. relay included in 5 UNITED STATES PATENTS.

said control circuit and operative with said ineffective drive magnet, and contact means actuated g g g 2 3? p 51 by said relay for short-circuiting said tube and for connecting busy potential to the test con- 

